Protective apparatus



y 1950 R M. WALTMAN 2,508,588

PROTECTIVE APPARATUS Filed Jan. 28, 194'? PLATINUM SPONGE, PLATINUM BLACK OR OTHER MATERIAL CERAMIC RESISTOR SAFETY SCRE E N S MANUAL RE-SET RELEASING EI ECTRO MAGNET A PLIANCES ROBERT M. WALTIVIA N Patented May 23, 1950 PROTECTIVE APPARATUS Robert M. Waltman, Towson, Md.,v assignor to Bendix Aviation Corporation, Baltimore, Md., a corporation of Delaware Application January 28, 1947, Serial No. 724,829

2 Claims.

This invention relates to systems for the distribution of illuminating gas and, more particularly, to protective apparatus for such systems designed to minimize the possibility of asphyxiation and explosion.

Illuminating gas finds a wide variety of applications in dwelling houses at the present time. It is generally piped from an entrance main to the various appliances by suitable piping having a number of elbows and joints. Settling of the dwelling may subject such installations to severe stress, and there may also be present faults and defects in the material of the pipin producing cracks and breaks at unpredictable times. In such event, the occupants of the dwelling are exposed to the danger of asphyxiation and, should the concentration of gas reach a' sufficient level, there further exists the danger of an explosion, which may destroy the dwelling and severely injure or kill the occupants. In addition to these unpredictable sources of gas leakage, it may also occur that appliance burners are supplied with gas without being ignited, or, having been ignited by some means, may be extinguished as by a strong current of air or a temporary interruption of the gas supply.

It is, therefore, an object of this invention to provide new and novel means for interrupting the gas supply to a structure, should gas leakage occur at any point therein.

It is a further object of the invention to provide new and novel gas sensing apparatus of catalytic type in which provision is made for preventing the propagation of catalytic induced exothermic reaction beyond the confines of a predetermined volume.

Other objects of the invention will in part be described and in part be obvious when the following specification is read in conjunction with the drawing which Portrays schematically a system illustrating the elements of the invention.

A fiow controller indicated at H! is connected in the path of gas supply at a point as near as possible to the entrance of the gas main. This controller is provided with a seat l2 adapted for engagement by the closure disk l4 carried on a stem l6 slidably mounted in the body of the flow controller III. A helical spring I 8 is normally compressed between the closure disk I4 and the base of the flow controller III and, consequently, urges the closure disk I4 in a direction tending to close the valve and interrupt the flow of gas therethrough.

The stem I6 is provided with a. detent projection 20 intermediate its length, and at its upper end is enlarged to form a button 22 permitting convenient reset. A latch 24 of paramagnetic material engages the detent projection 20 and is pivoted at 26 on the frame of an electromagnetic relay 28 having an operating coil 30. The operating coil 30 is connected by a circuit including the gas sensing device 32 with the secondary 34 of a transformer 36 having its primary 38 con nected with the power mains represented by the source 40. The gas sensing device 32 employs as its electrically active element a resistor 42 conveniently of the type diminishing in resistance with an increase in temperature. Such resistors may be produced by the firing of mixtures of ferric oxide with other metallic oxides and suitable fluxing agents, and are well known in the art, a considerable variety of them having been described by Becker, Green and Pearson in the November, 1946, issue of Electrical Engineering. Surrounding the resistor 42 there is a body 44 of a suitable catalytic agent which, for illuminating gas, may be platinum sponge or platinum black. The assembly comprising resistor 42 and catalyst 44 is surrounded by safety screens 46 and 48 which prevent the propagation of any exothermic chemical reaction induced by the catalyst 44 beyond their confines.

Operation The mode of operation of the system is immediately apparent. Normally, the resistor 42 presents a high resistance so that a very small current flows through the operating winding 30. Should gas escape into the atmosphere and diffuse to the region of the gas sensing device 32, an oxidation reaction is induced by the catalyst 44, heating it and the resistor 42 with which it .is

thermally associated. This diminishes the repressing the button 22 driving the stem i6 downwardly to again compress the spring I8, while the sloping portion of the detent projection 20 drives the latch 24 to the right, which slips into locking position after the upper surface of the a,eos,sss

detent projection has passed thereby. The apparatus is now ready for operation in accordance with the previously described cycle.

It is obvious that the utility or this apparatus is not limited to protection against escaping illuminating gas but may, by the selection of suitable catalysts, be applied to interrupt the flow or fluid in any system containing any volatile fluid whose composition is known beforehand, whenever such fluid appears in another system where its presence may be detrimental.

The invention may be embodied in other speeiflc forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalents of the claims are therefore intended to be embraced thereby.

What is claimed and desired to be secured by United States Letters Patent is:

1. In combination, a flow controller connected between a fluid source and fluid utilizing apparatus, means urging said flow controller toward flow interrupting position, latch means retaining said flow controller in flow permitting position, electromagnetic means for releasing said latch, a

4 thermally responsive resistor diminishing in resistance with increase in temperature, means connecting said electromagnetic means and said thermally responsive resistor in series with a source or electric energy, and a catalyst promoting an exothermic reaction of vapors of said fluid with the atmosphere thermally associated with said resistor.

2. In combination, a flow controller connected between a fluid source and fluid utilizing apparatus, a thermally responsive resistor diminishing in resistance with increase in temperature, a catalyst promoting an exothermic reaction 01' vapors of said fluid with the surrounding atmosphere thermally associated with said resistor, means for actuating said flow controller in response to changes in the resistance of said resistor, and means for limiting the propagation of said reaction trom said catalyst.

ROBERT M. WALTMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 970,122 Schmidt Sept. 13, 1910 1,888,984 Gruss Nov. 29, 1932 

